Abstract

Background: Diabetic foot is one of the most significant complications of diabetes, defined by ulceration associated with peripheral arterial disease and neuropathy. These ulcers can lead to infections and are the most common cause of non-traumatic lower limb amputations. In Libya, where diabetes prevalence is estimated at 16%, there is limited information regarding patient practices and risk factors regarding diabetic foot syndrome. Objectives: The primary aim of this study was to estimate the prevalence and risk factors of diabetic foot syndrome among diabetic patients attending the Souq Alkhamees Diabetic Center in Alkhoms City, Libya. Methodology: This prospective study was conducted at the Souq Al-khamees Diabetic Center in collaboration with the Libyan Academy for Postgraduate Studies. The study enrolled 60 diabetic patients with a history of diabetic foot syndrome. Data collection involved acquiring demographic information, diabetes history, and specific foot complications. Results: The cohort was predominantly male (58.33%) and aged 40–79 years. Type II diabetes was present in 86.11% of participants, and glycemic control was notably poor, with 63.89% of patients having HbA1c levels above 8.0 mg/dl. Key clinical findings included: Neuropathy: 76.66% of participants exhibited sensory impairment, with 33.33% demonstrating a complete loss of protective sensation. Dermatological Status: 100% of patients presented with thick infected nails and skin dryness, while 47.22% had foot deformities. Ulcer Characteristics: 80% of participants had a current or historical ulcer. Of active ulcers, 64% were superficial, while 36% were deep, involving structures such as tendons or bones. Mobility: 70% of participants had restricted or absent ambulation. Conclusion: The study population presents a highly complex and aggressive form of diabetic foot disease, primarily driven by uncontrolled hyperglycemia and characterized by severe neuropathy and tissue compromise. The high prevalence of deep ulcers and infection necessitates a clinical management strategy focused on surgical intervention and aggressive offloading. Furthermore, strict glycemic control and patient education regarding foot care are essential to preventing further complications and amputation.

 In this paper, a new continuous probability distribution has been proposed. The proposed distribution is considered as one of the extended distributions of Rayleigh distribution, which is well known in probability Theory and its applications. The distribution under consideration is titled "Exponential Log-compound Rayleigh distribution". proposed. The statistical properties of distribution parameters estimating using Maximum likelihood technique and Fisher information matrix are investigated theoretically. The evaluating of distribution performance is demonstrated on both simulated data and real data. Based on the values of bias, MSE and Fisher information matrix of the parameters estimates, the proposed distribution is considered to be working well.

Rotating machinery is a critical component in mechanical systems, widely used across industrial applications. Due to time-varying speed conditions and complex operating environments, it is highly prone to various failures. Without timely diagnosis and maintenance, such failures can lead to significant performance degradation or catastrophic outcomes. To address the challenges posed by non-stationary operating conditions and vibration signals, researchers have developed diverse fault diagnosis methods, including advanced non-stationary signal processing techniques and data-driven approaches. Among these, generalized demodulation (GD) has demonstrated particular effectiveness in extracting fault-related features from complex signals. This paper provides a comprehensive review of GD-based fault diagnosis methods for rotating machinery. It revisits the fundamental concepts and theoretical basis of GD, analyzes the limitations of traditional approaches, and systematically compares GD with other widely used methods. Furthermore, existing GD-based techniques are categorized into speed-dependent and speed-independent methods based on their reliance on rotational speed, with representative studies and applications discussed. Finally, future research directions and current challenges in GD-based diagnosis are outlined, offering valuable insights for researchers and practitioners in the field.

Planetary gear systems in industrial equipment, characterized by highly integrated structures, non-stationary operating conditions, and heavy-load characteristics, result in significant attenuation of fault-related vibration features, severely limiting the effectiveness of fault diagnosis. Traditional studies often use periodic modulation terms, such as the Hanning window function, to approximate the spatiotemporal distribution characteristics of meshing forces. Although these methods can effectively extract global vibration features of healthy gears (such as meshing frequency and its harmonics), they have significant limitations and are unable to analyze the nonlinear diffusion process of fault impacts through complex paths, resulting in distortion in the phase delay and amplitude attenuation patterns of fault impacts. To address these issues, this study investigates the vibration transmission characteristics of a planetary gearbox through rigid-flexible coupling simulation analysis, focusing on the transmission delay effects of impact responses to the vibration sensors at different housing locations. The study qualitatively clarifies the intrinsic relationship between transmission delay characteristics of the gear-sensor spatial relationship, providing a theoretical foundation for accurate analysis of vibration signals in planetary gear sets. The research highlights the significant spatiotemporal characteristics of the vibration responses when the fault collisions occur at different locations during the rotation and revolution of planet gears.

Fracture toughness is a critical mechanical property influencing the clinical durability of prosthodontic materials, especially those used in high-stress posterior regions. Differences in composition, microstructure, and fabrication technologies can significantly affect resistance to crack propagation. This experimental study evaluated the fracture toughness of three prosthodontic material groups (n = 10 each). Standardized samples were prepared and tested using the Vickers indentation technique under controlled laboratory conditions. Descriptive statistics were calculated for each group, and a one-way analysis of variance (ANOVA) was performed to determine significant differences among the groups. Post-hoc pairwise comparisons were conducted using Tukey’s Honest Significant Difference (HSD) test. Statistically significant differences in fracture toughness were observed among the three groups (p < 0.001). Group II demonstrated the highest mean fracture toughness (5.39 ± 0.34 MPa·m^1/2), followed by Group III (4.34 ± 0.36 MPa·m1/2). Group I recorded the lowest mean value (2.82 ± 0.56 MPa·m1/2). Tukey’s post-hoc analysis confirmed that all pairwise comparisons were significant (p < 0.001), indicating that each material group exhibited distinct mechanical performance profiles. The findings show that the fracture toughness of prosthodontic materials vary significantly depending on their composition and manufacturing technology. Materials in Group II outperformed the other groups, suggesting greater suitability for clinical situations where high resistance to fracture is required. Further studies incorporating additional mechanical tests and long-term clinical evaluation are recommended to validate these results under functional oral conditions. 

Abstract Micro-hardness is a fundamental property of prosthodontic restorative materials, as it affects their resistance to surface deformation, wear, and long-term clinical performance. This study aimed to compare the Vickers micro-hardness of three widely used CAD/CAM materials: lithium disilicate, monolithic zirconia, and multilayered zirconia. A total of 30 specimens (N = 30) were fabricated, with 10 samples allocated to each material group. Lithium disilicate specimens were prepared as rectangular plates (18 × 15 × 1 mm), whereas zirconia specimens—both monolithic and multilayered—were fabricated as discs (10 mm in diameter and 1.5 mm in thickness) following standardized CAD/CAM milling and sintering protocols. Vickers micro-hardness testing was conducted using a digital micro-hardness tester under material-specific conditions: a load of 1 kg and a dwell time of 10 s for lithium disilicate, and a load of 500 g with a 20 s dwell time for zirconia. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post-hoc test, with the significance level set at p < 0.05. Significant differences in micro-hardness were identified among the three materials (p < 0.001). Monolithic zirconia demonstrated the highest mean hardness (680 ± 19 HV), followed by multilayered zirconia (623 ± 47 HV), while lithium disilicate exhibited the lowest values (553 ± 32 HV). Post-hoc analysis confirmed that all pairwise comparisons were statistically significant. The findings indicate that monolithic zirconia possesses superior micro-hardness compared to multilayered zirconia and lithium disilicate, supporting its suitability for high-stress clinical applications. Multilayered zirconia offers a balance between mechanical performance and esthetics, whereas lithium disilicate remains optimal for highly esthetic anterior restorations. These results provide clinicians with evidence-based guidance for selecting CAD/CAM materials in fixed prosthodontic rehabilitation. 

The surface integrity of CAD/CAM restorative materials is critical for their esthetic and mechanical performance. Acidic challenges in the oral environment can degrade ceramic surfaces, increasing roughness and potentially compromising restoration longevity. This study aimed to evaluate and compare the effect of 4% acetic acid immersion on the surface roughness (Ra) of lithium disilicate glass-ceramic and hybrid ceramic (Vita Enamic) CAD/CAM restorative materials. A total of 40 rectangular specimens (18×15×1 mm) were fabricated, 10 per material per condition. Specimens were polished according to manufacturer protocols and immersed in 4% acetic acid (v/v) at 80∘C for 16 hours, following ISO 6872 standards. Surface roughness was measured using a Roughness Tester (PCE-RT 2000). Data were analyzed using independent t-tests, and effect sizes were calculated (Cohen’s d). Both materials exhibited significant increases in surface roughness after acid exposure. Lithium disilicate showed Ra values increasing from 0.0676±0.0187 µm to 0.5129±0.0912 µm (p<0.001, d=4.79). The hybrid ceramic exhibited a larger increase, from 0.2063±0.0568 µm to 1.4409±0.4951 µm (p<0.001, d=2.48). The hybrid material was therefore more susceptible to acid-induced degradation than lithium disilicate. Immersion in 4% acetic acid significantly deteriorates the surface of both lithium disilicate and hybrid ceramic, with hybrid ceramic showing greater roughness changes. Lithium disilicate may be preferred for patients at high risk of acidic challenges. These findings emphasize the importance of material selection and surface management to optimize restoration longevity.